Feed mechanism for lathes



Oct. 26, 1937. R. K. LE BLOND ET AL 2,097,375

I FEED MECHANISM FOR LATHES I Filed July 16, 1936 10 Sheets-Sheet l INVENTORS. my lac/Mk0 KA'BLo/vo,

1 419,?! C AEMPA-I? ATTORNEYS.

Get. 26, 1937.

R. K. LE BLOND ET AL 2,697,375

FEED MECHANISM FOR LATHES Filed-July 16, 1956 10 Sheets-Sheet 2 INVENTORS. Egan/Po M i 551. one, flaw/Fr 67 AEMFER.

M1 MW ATTORNEY-5.

Oct. 26, 1937.

Filed July 16, 1956 1o Sheets-Sheet 4 IV a IN VEN TORS ATTORNEYS,

Oct. 26, 1.937. R. K. LE BLOND ET AL FEED MECHANISM FOR LATHES Filed July 16, 1936 10 Sheets-Sheet 5 D .mxi 2 WWW 2 I Mm m on an. 4mm 3 N r Q 9 mm :m ww ow um a QB I I l I I I l I 1 $1 mm +5 MN am. a rH m Q M ON u .3 E R Q. QR. mm M. -D k NF Oct. 26, 1937. R. K. LE BLOND ET AL 7,

FEED MECHANISM FOR LATHES Filed July 16, 1936 10 Sheets-Sheet 6 b -co 8:

m l 8 4 W N O Q 00%) (g a a v 2 as a g E f g '5 a KQ c g HI m N 4 LO I l q) m 4 2% EQTN m' 322: 9.

"I I I INVENTORS. 5D 6) I ,4 lllclmea If LEBLOND,

ATTORNEYS.

0a. 26, 1937. r R. K. LE' Emma ET AL 2,097,375

FEED MECHANISM FOR LATHES Filed July 16, 1936 10 Sheets-Sheet 7 Q ATTORNEYS.

Oct. 26, 1937. R. K. LE BLOND ET AL 2,097,375

FEED MECHANISM FOR LATHES Filed-July is, 1936 10 Sheets-Sheet s INVENTORS.

\ {Paw/mm A? 1.5340010,

MMJV-M ATTORNEYS.

Oct-1 137- R. KQLE BLOND ET AL 2,097,375

FEED MECHANISM FOR LATHES Filed July 16, 1936 10 Sheets-Shet 10 Q INVENTORS. Q fic/mma A? 1554mm,

7 wq wa ATTORNEYS.

Patented Oct. 26, 1937 UNITED STATES PATENT OFFICE FEED MECHANISM FOR LATHES Application July 16, 1938, Serial No. 90,940

15 Claims.

This invention pertains to tool feeding mechanism for lathes, and in particular to mechanism for actuating the carriage and cross slide of engine lathes.

5 One object of our invention is to provide in a lathe apron, a mechanism for obtaining the necessarily complete range of threads and feeds for the tool carriage. Another is to provide control means conveniently located on the apron for selecting the various threads and feeds desired.

Still another object is to provide means in connection with the thread and feed change mechanism so that selection of various threads and feeds may be accomplished while the lathetool is 15 in cutting operation.

An object is also to provide a simplified and easily operated control lever for alternately selecting the cross or longitudinal feeding motions for the carriage.

20- Again, an object is to provide a simplified interlocking mechanism to prevent simultaneous engagement of the half-nuts on the lead screw and the feeding motion to the carriage or cross slide.

25 A further object of our invention is to provide a novel rapid traverse mechanism for longitudinally moving the tool carriage in either direction on the lathe bed.

The rapid traverse mechanism is unique in that so it may be rendered operative to traverse the carriage in either direction irrespective of whether the feed mechanism is engaged or disengaged.

The rapid traverse mechanism is also arranged so that damage is prevented when the carriage is traversed into obstructions such as the headstock or tailstock of the lathe, or when the latter is operated with the half-nuts in engagement with the lead screw.

It is also our object to provide means in. con

nection with the traverse mechanism to prevent a rapid rotation of the hand wheel for longitudinal movement of the carriage when the carriage is being normally actuated in rapid traverse.

These and other objectsof our invention which will be set forth hereinafter or will be apparent certain construction and arrangement of parts of which we now describe an exemplary embodiment.

Reference is made to the drawings, wherein Fig. 1 is front elevation in perspective of a typical application of our invention to an engine lathe.

Fig. 2 is an enlarged front elevation in perspective of the lathe apron.

to one skilled in the art, we accomplish by that Fig. 3 is a left hand end elevation of the rapid traverse control box mounted on the front of the lathe bed.

Fig. 4 is a front elevation of the rapid traverse control box showing, in addition, a portion of the 5 left hand end of the lathe apron.

Fig. 5 is a diagrammatic section of the rapid traverse control box on the line VV of Fig. 3.

Fig. 6 is a diagrammatic section of a portion of the change speed transmission mechanism of the lathe apron on the line VIVI of Figs. 9 and 10.

Fig. 7 is a vertical transverse section through the apron and carriage of the lathe on the line VII-VII of Fig. 8.

Fig. 8 is a diagrammatic section of the lathe apron on the line VIII-VIII of Figs. 9, 10, 11, and 12.

Fig. 9 is a vertical transverse section through the lathe apron on the line IXIX of Figs. 6 and 8.

Fig. 10 is a vertical transverse section through the lathe apron on the line X-X of Figs. 6 and 8.

Fig. 11 is a vertical transverse section through the lathe apron on the line XIXI of Fig. 8.

Fig. 12 is a vertical transverse section through the lathe apron on the line XII-XII of Fig, &

Fig. 13 is an end elevation partly in section on the line XIII-XIII of Figs. 4 and 8, showing particularly the control levers for the rapid traverse mechanism.

Fig. 14 is an end elevation partly in section on the line XIV-XIV of Fig. 4.

Fig. 15 is an end elevation partly in section on the line XVXV of Fig. 8.

The invention is shown in the exemplary embodiment as applied to a conventional engine lathe comprising the bed I supported on suitable legs 2 and having a headstock 3 mounted on the bed, and a tool carriage 4 mounted for longitudinal movement on the ways 5 of the bed. The. lathe apron 6, for controlling the motion of the carriage 4 and cross slide I, is mounted on the carriage 4 at the front of the lathe in the usual manner. The rapid traverse control box 8 for the apron mechanism is mounted on r the left hand end and on the front of the lathe bed I.

Rapid traverse control boa: Referring particularly to Figs. 3, 4, and 5, the

source of power for operating the apron mechanism to feed the carriage 4 and cross slide 1 is derived from the headstock transmission in apron mechanism from the rapid traverse control box 8 through the usual feed rod l2 which is coupled by suitable means i2 to the feed drive shaft i4 journaled in suitable bearings l5 and it in the rapid traverse control box 9, which shaft i4 has the gear I! fixed thereto. This gear is driven by the gear ll so as to transfer power from the headstock transmission to drive the feed rod l2 as will be readily understood.

In this novel arrangement the usual rack and pinion means for longitudinal feeding of the carriage has been dispensed with. In their stead a circular helical rack or rapid traverse screw I8 is provided, located longitudinally of the lathe bed i, and adapted to be rotated in either direction at a relatively rapid rate for rapidly travers ing the carriage in either direction. It-is stopped during the normal feeding of the carriage 4. The left-hand end of the rapid traverse screw it is journaled in suitable bearings l9 and 20 mounted in the rapid traverse control box 8. A suitable anti-friction thrust bearing 2|, mounted adjacent the bearing l9 and also a similar thrust bearing provided in the right hand end mounting (not shown) of the rapid traverse screw l9, may be employed to prevent axial movement of the screw during the feedingand rapid traverse motions of the carriage 4.

The means for driving the rapid traverse screw i9 in either directioncomprises the. clutch shaft 22 journaled in suitable bearings 22 and 24 mounted inthe rapid traverse box 9 and having a suitable driving pulley 25 mounted thereon which is driven at all times during the operation of the lathe. Rotatably Journaled on the bearing portions 26 and 21 of the clutch shaft 22 are the forward and reverse clutch members 29 and 29 which may be alternately connected in driving engagement with the shaft '22 by actuation of the conventional multiple-disc clutches 34' and 3! upon axial movement of the usual clutch actuator spool 32. Formed integral with the clutch members 29 and 29 are gears 22 and 34. The gear 34 is adapted to drive the gear 35 fixed on the rapid traverse screw ll, andthe gear 39 is adapted to drive the idler gear 90 rotatably mounted on the stud'fl fixed in the rapid traverse box 8,. which idler gear I. in turn drives the gear 39 fixed on the rapid traverse screw it (see especially Fig. 3). It can therefore be seen that by rendering either one or the other of the multiple-disc clutches 99 and 2| operative, as described, the rapid traverse screw it may be caused to rotate in either direction. During normal operation of the lathe, when no rapid traversingis being performed, the, spool 22 is in neutral position, rendering both multiple-disc clutches inoperative, so that the rapid traverse screw is normally not rotating while carriage feeding operations are taking place.

Apron transmission the same time permitting. longitudinal movement of the apron 6 and carriage 4. Fixed to the sleeve 39 intermediate the bearings 49 and 4!, and adjacent the latter, is a cone of gears 44.

Mounted parallel with the sleeve 39 is the dive-key shaft rotatably Journaled in the bearings 46, 41, and 49 in the apron 6, the

bearings 46 and 41 being adapted to prevent substantially all axial movement in the shaft 45. Rotatably journaled on the bearing portion 49 of the shaft 45 intermediate the bearings 46 and 41, and adjacent the latter, is a series of gears 50 adapted individually to engage. the gears of the gear cone 44 in driving relationship so that they rotate at all times during the rotation of the cone of gears 44. Suitable spacing collars BI, 52, and 53 and the gear sleeve 54 fixed on the shaft 45, keep the gears 59 in proper axial alignment at all times with the cone of gears 44.

A dive-key 55, adapted to slide axially of the shaft 45 in a. suitable keyway 56 and urged radially outward from the center of the shaft by a suitable spring 56a, provides means whereby any one of the gears 50 may be connected in driving relation to the shaft 45. This is of course accomplished when the nose 51 of the dive key engages a slot 99 (Fig. 10) in one of the gears 59. A novel feature of this arrangement is that a plurality of slots 59 are provided in the gears 59 to permit more rapid engagement of the dive-key II with one of the gears 50 when the dive key 55 is shifted to a selected position. Another novel feature is that the driving faces 59 of the slots 59 in the gears 99 are not parallel but are arranged to diverge inwardly toward the center of the shaft 4|, the nose Siof the dive key I! being made wedgeshaped so as to fit snugly between the faces 59 of the slots 59 when fully engaged therein. The purpose of this is to permit quick engagement and easy withdrawal of the dive key even while the lathe is taking heavy cuts, an advantage not possible in former constructions wherein the driving faces 59 were arranged parallel. The mechanismjust described provides the speed changes for obtaining the fine range of feeds and threads.

In order to give the complete range of feeds and threads necessary to a lathe, mechanism providing a series of coarse feed and thread changes are utilized in addition to the flue changes above described. This mechanism comprises a shaft 9| iournaled in suitable bearings II and I2 and confined thereby from substantially all axial move ment, mounted in the apron 8 parallel to the shaft 45. Fixed to the shaft 99 are three different sized gears 93, 64, and 9!, the largest gear 59 being constantly engaged withthe gear 66 formed integral with the sleeve 94 so that rotation of the shaft 45 will cause rotation of all the gears 69, 64, and and the shaft 99.

Located parallel with the shaft 69 is the bevel pinion shaft 69, iournaled in the bearing C1 in the apron 6 and having a bevel pinion 69 fixed to the end opposite the bearing 01, which pinion 68 in turn is journal ed in the bearing 89 in the apron 6. The bearings 61 and 69 are so arranged as to prevent substantially all axial movement in the shaft 66. The portion of the shaft 66 intermediate the bearings 61 and 99 is provided with splines 10 upon whichis slidingly mounted the multiple sliding gear 1i, comprising the gears 12, i2, and 14 which gears are adapted respectively to engage the gears 92, 44, and S5 of the shaft 89 so that three major speed changes may be obtained between the shafts 69 and 66 when the proper axialposition is selected for the multiple sliding gear II.

The means for driving the leadscrew 15 for the thread chasing from the change speed mechanism described comprises a sleeve I6 rotatably journaled in suitable bearings 11 and II in the apron 6 and a gear I9 fixed to the sleeve I8 which is driven by the gear 80 slidably mounted on the splinesof the shaft 66. The gears I9 and 80 may be disengaged or engaged at will by sliding the gear 80' axially on the splines 10. The leadscrew is slidingly supported in the bore of the sleeve I6, a key 8! fixed in the sleeve I6 beingadapted slidingly to engage the keyway 82 of the leadscrew so that the leadscrew 15 can be driven at any time during longitudinal movement of the apron 6. The means for engaging the halfnuts 83 on the leadscrew I5 comprises the usual scroll cam 84, cam shaft 85, and hand lever 86 as fully disclosed in Patent 980,971 issued Jan. 10, 1911.

The mechanism for alternately effecting longitudinal and cross feeding of the carriage and cross slide is substantially the arrangement set forth in Patents 1,218,784 issued Mar. 13, 1917 and 1,944,231 issued January 23, 1934. The bevel pinion 68 is arranged to drive the bevel gear 81 fixed on the shaft 88 suitably journaled in the front and rear walls of the apron 6. Fixed on the shaft 88 is the pinion gear 89 which drivingly engages the shiftable double clutch gear 90 fixed to the shifter shaft Si by a suitable pin 92, the shifter shaft 9I being journaled for both rotary and axial movements in bearing bushings 93 and 94 mounted in the front and rear walls of the apron .6. Rotatably mounted on a projecting bearing portion 95 of the bushing 93 is the cross feed clutch gear 96 which engages the pinion gear 91 on the cross feed screw 98. Rotatably mounted on the shifter shaft 9| adjacent the bushing 94 is the longitudinal feed clutch gear v 99 having the pinion gear I00 formed integral therewith. This is adapted to drive the gear IOI fixed to worm shaft I02 journaled in suitable bearings I03 and I04 in the front" and rear. walls of the apron. The worm I05- fixed to the shaft I02 adjacent the .bearing I04 engages the rapid traverse screw I8 as a pinion engages-a rack so that the apron 6 and carriage 4 are moved longitudinally upon rotation of the shaft I02. Pins I06 loosely carried in holes I01 in the doubleclutch gear, 90 are used to keep the clutch gears 96 and 99 in proper axial position relative to the double clutch gear 90. It can thus be seen that when the double clutch gear 90 is moved axially to engage the clutch gear 96 the cross slide will be actuated and when the double clutch gear 90 is moved axially to engage the clutch gear 99 the apron and carriage will be actuated for longitudinal feeding.

Apron control mechanism A new and simplified control handle I08, for

shifting the double clutch gear 90, has a hub portion I09 which is joumaled in the bore H0 in the bushing 93 and has a bore through which the reduced end I I I of the shifter shaft passes. A suitable lock nut I I2 threaded to the end of the shaft 9I serves to position the handle I08 axially on the shaft 9| by confining the hub portion I09 between the lock nut H2 and the shoulder II3 of the shaft 9|, while at the same time permitting rotation of the reduced portion III of the shaft in the hub portion I09. On the periphery of the hub portion I09 is provided a cam slot II4 which is engaged by a pin II5 threaded in the apron 6 and passing through the bushing 93. The

cam slot H4 is so arranged thatas the hub portion I09 is rotated by means of the handle I08, the hub portion I09 and the shifter shaft 9| connected thereto will be shifted axially.

The arrangement is such that both the longitudinal and cross feed is disengaged when the handle I08 is in the down position as shown particularly in Figs. 1, 2, '7, and 8. When it is desired to engage the longitudinal feed, the handle I 08 is moved upward to the right and when it is desired to engage the cross feed the handle I08 is moved upward to the left. A conventional spring-backed ball detent H6 is provided to coact with appropriatenotches III in the hub portion I09 properly to retain the handle I08 in the longitudinal feed, cross feed, and neutral positions;

. A simplified interference device, Fig. 8, is provided between the half-nuts 83 and shifter shaft 9I-comprising a rod H8 slidingly fitting in suitable bores H9 and I in the apron 6. An annular slot formed on the shifter shaft 9| permits the rod II8 to move radially toward the axis of the shaft .9I only when the shifter shaft SI and the double clutch gear 90 are in neutral position, under which condition the other end of the rod H8 is withdrawn from the notch I 22,allowing manipulation of the half-nuts 83 for engage ment with or disengagement from the leadscrew I5. When the half-nuts 83 are engaged, the slot I22 does not line up with the rod I I8 so that the rodI I8 cannot be movedout of the slot IZI thus preventing the shaft 9i from being moved axially so as to engage the feed. With the half-nuts 83 Withdrawn, the rod II8 can enter the slot I22 of the half-nuts 83 and will be held in the slot I22 whenever the shifter shaft 9| is moved to either feed engagement position, which precludes any possible engagement of the half-nuts 83 when any feed position is selected.

The apron 6 has the usual hand wheel I23 for manual longitudinal movement of the apron 6,

and carriage 4. This is mounted on the hand wheel shaft I24 journaled in suitable bearings I25 and I28 in the apron 6. The shaft I24'is connected at all times to thelongitud nal feeding transmission through the gear I21 fixed on the hand wheel shaft I24, and the idler gear I28 journaled on a suitable bearing I29 on the shaft I30 fixed in the apron 6. The'idler gear I28 in turn is in driving engagement with the longitudinal feed clutch gear 99. Thus, through the mechanism described, the apron 6 and carriage 4 may be manipulated longitudinal y at all t mes by manual rotation of the hand wheel I23.

. Referring particularly to Figs. 1, 2, 6. '7, and 11, the means for selecting the fine speed changes in the apron transmission for the various threads and feeds desired comprises the control lever .I3l mounted on the rock shaft I32 on the front of the apron 6. On the inner end of the rock shaft I32 is fixed the gear I33 which engages the circular rack I34 of the dive key shifter sleeve I35.

which sleeve I35 is slidingly mounted on the divekey shaft 45 and is caused to rotate therew th by means of the key I 36 fixed in the shaft 45 and slidingly engaging in the keyway I 31 of the sleeve I35. The sleeve I35 is connected to the dive key 55 by means of the screw I38 threaded in the sleeve I35 and projecting inwardly to engage the notch I39 provided in the outer end of the dive key. It can thus be seen that by swinging the handle I3I the gear I33 will be rotated.

- This in turn will cause axial movement in the sleeve I35 and the dive key 55 connected thereto, whereby to engage the various gears 50 in driving relation on the shaft 45 as already described. Suitable retaining means for holding the lever I3I in selected position comprise the usual springseated plunger handle I40 having the plunger I4I adapted to engage the locating holes I42 corresponding to the various gears 50.

The means for selecting the coarse changes of speed in the apron transmission for the various threads and feeds desired is clearly shown in Figs. 1, 2, 6, and 9 and comprises the control lever I43 which is mounted in the rock shaft I44 on the front of the apron 6. On the inner end of the rock shaft I44 is fixed a lever arm I45'having pivotally mounted at its outer end a shifter yoke I46 which engages the side faces of the gear 14 of the sliding gear II so that movement of the lever I43 will cause sliding of the gear 1| selectively to engage the various combinations of gears 63-12, 64-13, and 6514 as already described. The usual spring-seated plunger handle I41 is provided for the lever I43 having the plunger I48 adapted to engage the locating holes I49 corresponding to the gear combinations indicated above. It is tobe noted that the index plate I50 for selecting the positions of the levers I3I and I43 for the desired feeds and threads is conveniently located for the operator on the front of the lathe apron.

This feed mechanism for a lathe is unique in that the leadscrew 15 for thread chasing is driven from the apron transmission rather than from transmission mechanism fixed to the bed I of the lathe. In the apron is provided means whereby the leadscrew 15 may be alternately connected or disconnected from the apron transmission mechanism. Referring particularly to Figs. 1, 2, 6,

and 10, a lever I5I is mounted on the rock shaft I52 on the front of the apron 6. On the inner end of the rock shaft I52 is fixed a lever arm I53 which has a shifteryoke I54 pivotally mounted on its outer end which in turn engages the side faces of the gear 80 so that movement of the lever I5I will cause the gear 60 to be moved axially on the splines 10 of shaft 66 to engage or disengage the gear 60 from the gear 19.

As described above, the longitudinal feeding of the apron 6 is accomplished by slowly rotating the shaft I02 and the worm I05 fixed thereon by means of the power feed mechanism or the handwheel I23, the worm I05 rolling axially along the rapid traverse screw I6 in the manner of a rack and pinion. When it is desired longitudinally to rapid traverse the apron 6 and carriage 4 in either direction the rapid: traverse screw I6 is rotated in either direction'at a relatively rapid rate while the shaft I02 and the worm I05 are held from rotating. In this case the worm I 05 functions as a nut which is caused to travel axially along the rapid traverse screw I8 so as to move the apron 6 and carriage 4 longitudinally in rapid traverse motion.

The control mechanismfor actuating the driving means for rotating the rapid traverse screw I 8 in either direction comprises the rapid traverse control lever I55 which is pivotally mounted on a suitable stud I56 for up and down motion on the left hand end of the apron 6, Figs. 1, 2, 4, and 13. The control handle I55 is connected by means of the rod I51 to the lever arm I58 pivotally mounted in the depending boss I59 of the apron 6. The lever arm I58 is secured from axial motion in the boss I56 by suitable retaining means I60 and has a bore I6I in which'is fixed the key I62 which arrangement slidingly receives the periphery and keyway of the rapid traverse control rod I63, with the result that the rod I63 may be rocked in either direction by manipulating the lever I55 irrespective of whether the apron 6 is stationary or moving longitudinally.

The'left hand end of the rapid traverse control rod I63 is journaled in the depending boss I64 of the control box 6. On the end of the control rod I63 adjacent the boss I64 is fixed the lever arm I66 which is connected by the rod I66 to a bell-crank lever comprising the arms I61 and I66 pivotally mounted on the shaft I66 in the control box 8. Suitable means I10 is provided on the end of lever arm I66 to engage in the annular slot "I for axial movement of the sleeve 32 to engage the. clutches 30 and 3I. It can thus be seen that by moving the lever I 55 up or down one or the other of the clutches 30 and 3| is rendered effective to cause rotation of the rapid traverse screw I6.

It is to be noted that longitudinal rapid traverse will only be imparted to apron 6 (when the rapid traverse screw I8 'is rotating) providing the worm I05 on the shaft I02 is held against rotation. Means is provided for automatically preventing rotation of the worm I05 when the apron is being rapidly traversed in either direction. Referring particularly to Figs. 2, 4, 8, 9, and 13, a brake shoe I12 having a hub portion I13 pivotally mounted on a shaft I14 fixed in the apron 6 is adapted to contact the periphery of the gear I21. Slidingly mounted in suitable bores I16 and I 16 in the apron 6 and passing through a clearance hole I11 in the depending. actuating lever I16 formed on the hub I13, is the brake actuating plunger I19. A spring I60 surrounding the plunger I19 between the bore I15 and the depending lever I16 provides a yielding means to hold the brake shoe I12 normally from contact with the periphery of the gear I 21. Another spring I II is also provided around the plunger I19 between the depending lever I16 and the collar I62 fixed to the shaft I19, the purpose of which is to provide resilient means for holding the brake shoe I12 on the periphery ofthe gear when the plunger is moved axially to the right, Fig. 8. The plunger I19 projects outwardly from the bore I16 in the apron 6, and has a pointed end I63 which is engaged by the V-notch I64 formed on the lug I65 depending from the rapid traverse lever I55. When the traverse lever I55 is in neutral position the pointed end I63 of the plunger I19 is fully entered into the V-notch I64 so that the plunger is fully extended to the left, disengaging the brake I12 from the gear I21. When the traverse lever I55 is moved either up or down to cause traversing of the apron, the pointed end I63 will be caused to ride up the tapered sides of the V-notch I64 so that the plunger I 19 will be moved to the right engaging the brake shoe I12 on the gear I21. This, through the gears I21, I26, 96, I00,and III, automatically prevents rotation of the worm I05 when the traverse mechanism is actuated. The

tensionof the spring I3I is such asto apply presby the rapid traverse screw I6 driving the worm wheel I05, thus preventing damage to the lathe mechanism.

It is to be further noted that rapid traversing of the apron 6 and carriage 4 can be accomplished without the use of the automatically operated braking device just described merely by manually holding the handwheel I23 from rotation. The efiort required upon the part of the operator to hold the hand wheel 523 during traversing operations is negligible because of the large reduction gearing existing between the worm I05 and traverse screw it, the gears we and W; and the gears 99 and H27.

It is also noted that the longitudinal and cross feeding mechanism may be engaged at any time, the engagement of the longitudinal feeding motion by engagement of clutch gear 96 with clutch gear at serving as a means to prevent substantially all rotation of the worm we as necessary when traversing the apron G. The relatively slow rotation of the worm W due to the feeding mechanism has substantially no effect upon the much more rapid motion produced in traversing. It can therefore be seen that the apron t and carriage d can be rapidly traversed at all times whether the feed mechanism be engaged or not without in any way damaging the mechanism of the lathe.

in the event the rapid traverse mechanism be engaged at the same time the half-nuts as are engaged on the lead screw 715 no damage would result to the lathe mechanism as the gearing between the worm W5 and the shaft 92d will merely rotate at high speed, spinning the handwheel,

the brake shoe H2 being insufficient to stop such rotation ofthe gear fill. Thus the operator will have an indication that the lathe is not being operated properly.

Having described our invention what we claim as new and desire to secure by Letters Patent is:

i. In a lathe, a bed, a carriage movable thereon, an apron mounted on said carriage, a rotatable screw mounted on said bed against relative axial movement and parallel to the path of movement of said carriage, means for rapidly rotating said screw, a rotatable shaft mounted in the apron transversely of said screw, a worm gear fixed on said shaft and engaging said screw, means for manually rotating said shaft to effect a longitudinal movement of said carriage on the bed, and means. for holding said shaft against rotation whereby to efiect a rapid traverse of said carriage when said screw is rotating.

2. In a lathe, a bed, a carriage reciprocable thereon, an apron mounted on said carriage, a ro-' tatable screw mounted on said bed against relative axial movement and parallel to the path of reciprocation of said carriage, means for rapidly rotating said screw selectively in both directions, a rotatable shaft mounted in the apron transversely of said screw, a worm gear fixed on said shaft and engaging said screw, means for manually rotating said shaft to efiect a longitudinal movementof saidcarriage in either direction on the bed, and means for holding said shaft against rotation whereby to effect a rapid traverse of said carriage in either direction when said screw is rotated in one or the other directions, said means comprising a brake.

shaft against rotation, whereby said carriage may be actuated in rapid traverse when said screw is rotating and said shaft is held from rotating, and whereby said carriage may be actuated for feeding when said screw is non-ro-.

tating and said shaft is rotated.

4. A tool feed mechanism comprising a frame member, a tool support member reciprocable thereon, a rotatable screw mounted on one of said members against relative axial movement and parallel to the path of reciprocation of said tool carrier, means forrotating said screw, a rotatable shaft mounted on the other of said members transversely of said screw, a worm fixed on said shaft and engaging said screw, and means for rotating said shaft, whereby said support member may be actuated in rapid traverse when said screw is rotated and said shaft is non-rotating, and whereby. said support member may be actuated for feeding when said screw is non-rotating and said'shaft is rotated.

5. A tool feed mechanism as set forth in claim 4 in which the tool support member is actuated in rapid traverse when said screw and said shaft are simultaneously rotated.

6. A tool feed mechanism comprising a frame member, a tool support member reciprocable thereon, a rotatable screw mounted on one of said members against relative axial movement and parallel to the path of reciprocation of said tool carrier, means for rotating said screw, control means for rendering said means for rotating said screw effective, a rotatable shaft mounted on the other of said members transversely of said screw, a worm fixed on said shaft and engaging said screw, means for rotating sa'd shaft,

and means actuated by said control means for' holding said shaft against rotation when said screw is rotating.

7. In a lathe, a bed, a carriage movable thereon, an apron mounted on said carriage, a rotatable screw mounted on said bed against relative axial movement and parallel th the path of movement of said carriage, means on said bed for rotating said screw, a rotatable shaft mounted in the apron transversely of said's'crew, a worm fixed on said shaft and engaging said screw,

,. manual and power means for rotating said shaft,

means for alternately engaging or disengaging said power means, and means for arresting rotation of said shaft when said power means is disconnected.

8. In a lathe, a bed, a carriage movable thereon, an apron mounted on said carriage, a rotatable screw mounted on said bed against relative axial movement and parallel to the path of movement of said carriage, means mounted on said bed for rotating said screw, a rotatable shaft mounted in the apron transversely of said screw, a worm gear fixed on said shaft and engaging said screw, means for rotating said shaft, control means mounted on said apron for rendering said rotating means for said screw effective, a friction brake for holding said shaft against rotation, and means cooperating with said control means for rendering said rotating means and said friction transversely of said screw, means for rotating said t, a worm gear fixed on said shaft and. en-

gaging said screw, means for rotating said shaft, and means for holding said shaft against rotation when said screw is rotating whereby to effect a rapid traverse of said carriage, said holding means being ineffective to hold said shaft against rotation during rotation of said screw when said carriage is obstructed from free rapid traverse motion.

10. In a lathe, a bed, a carriage mounted thereon, an apron mounted on said carriage, a feed rod rotatably mounted longitudinally of said bed, means for rotating said feed rod, change speed gearing in said apron comprising a cone of gears driven by said feed rod, a shaft, a plurality of gears iournaled on said shaft and arranged to be driven by said cone of gears, dive-key mechanism adapted selectively to connect each of said plurality of gears in drivingrelation to said shaft, a second shaft rotatably mounted parallel with said first mentioned shaft, a multiple-gear mounted on said second shaft and adapted to be driven by said first mentioned shaft, a third shaft rotatably mounted parallel with said aforementioned-shafts, a second multiple-gear slidingly mounted in driving relation on said third shaft adapted selectively to engage said first mentioned multiple-gear to effect a change speed drive between said second and third shafts, and means driven by said third shaft to effect feeding motion in said carriage.

11. In,a lathe, a bed, a carriage mounted thereon, ,an apron mounted on said carriage, a feed rod rotatably mounted longitudinally of said bed, means for rotating said feed rod, a leadscrew rotatably mounted longitudinally of said bed, change speed gearing-in said apron comprising a cone of gears driven by said feed rod, a shaft, a plurality of gears iournaied on said shaft arranged to be driven by said cone of gears, dive-key mechanism adapted selectively to connect each of said plurality of gears in driving relation to said shaft, a second shaft rotatably mounted parallel with said first mentioned shaft, a multiple-gear mounted on said second shaft and adapted to be driven by said first mentioned shaft, a third shaft rotatably mounted parallel with said aforementioned shafts, a second multiple-gear slidingly mounted in driving relation on said third shaft adapted to selectively engage said first mentioned multiple-gear to effect a change speed drive between said second and third shafts, means driven by said third shaft to effect feeding motion in said carriage, and means for rotating said leadscrew from saidthird shaft.

12. In a lathe as set forth in claim 10, control means mounted on the front of the lathe apron to actuate said dive-key mechanism at all times during the operation of the lathe.

13. In a lathe as set forth in claim 11, a control means mounted on the apron' for actuating said dive-key mechanism, a control means mounted on the apron for shifting said second multiplegear, and control means for rendering said means for rotating said leadscrew eflective or ineffective.

14. In a lathe comprising a carriage, a leadscrew, an element shiftable on the carriage to connect or disconnect the leadscre'w and carriage, feed-rod-connecting, carriage-feeding and cross-feeding mechanisms on said carriage, three members coaxially and severally rotatable on sai carriage with clutching means on their adleadscrew and carriage and comprising a bar v axially slidable in said carriage and adapted alternately to engage appropriate slots in said shiftable unit and shiftable element so as to prevent shifting of said element except when said shiftable unit is in its mid-position, and preventing shifting of said shiftable unit from said mid-position when said element is in leadscrew-connecting position.

15. In a lathe apron, a support and three mechanisms on the support, three members severally and coaxially rotatable on the support and connected, respectively, to said three mech-- to be inoved axially when moved in said per-' pendicular plane whereby to shift said axially shiftable unit to said different positions, and detent-means also associated with said support and said lever to hold said unit in each position.

RICHARD K. LE BLOND. HARRY C. 

